split mixer power supply

[gnd]

Hi.

I'm thinking about certain idea, and would like to ask you if you think it is ok.

My mixer has 16 channels, and I'm changing things inside, biasing to class A, and line channels will be added, so I will need stronger power supply. Instead of using one single external 5-amps power supply, I'm thinking of putting externally just big toroid, strong graetz and big capacitors and 5A fuses, and then put regulator sets (7818, 7918) inside the mixer.

Now, I'm thinking to split power load between several regulators sets, each feeding just few channels. Say, instead of one strong supply regulator set supplying all channels, including summing buss, I would make separate regulator sets for channels in groups of 4, and also use sepatare regulator set (with 24V voltage) on summing buss, and separate regulator set for headphone power outputs. Thus power consumption would be spread over several regulators, and I could get away with miminum sized heatsinks on regulators, and smaller capacitors.

Is this idea to have several regulator sets (possibly with different voltages) possible at all? Can there be any problems expected? What do you think?

thnx

 

[Brian Roth]

More than a few desks took the concept even a step further, with regulators on EACH module, so I think your concept has merit.

Bri

 

[Boswell]

Yes, this is a technique widely exploited on modern designs. It usually goes by the name of "point of load regulation" or "point of load conversion" where switching regulators are involved. It shouldn't give you any problem if done carefully.

In another genre, some modern vehicles have a 12V or (recently) a 42V bus going round to all electrical devices, with local control and regulation.

 

[Viitalahde]

If starting from square one, I think the regulator per module thing is really good.

 

[gnd]

thanx all for reply.

It is great information. Regulators per each module could be possible, but maybe too much in my case. But will certainly split it over several regulator sets.

What about ground? Several regulator sets means several ground points. In my mixer I already have five ground rails. There is power ground, input ground, eq ground, leds ground, fader/pot ground. They all come together on monitor module, and then go to power supply zero and chasis.

Now, if i split to several regulators, my zero gets multi too. What would be best system to ground all modules, with all their different ground rails?

pls, any ideas are most velcome.

thnx

 

[Svart]

all channels should go to a ground buss, something thick and very conductive that is tied to the channels with thick wires and solid connections. give your ground buss the least impedence you can possibly give it. It sounds like they are already attempting to use the star technique, you should continue with that.

 

[gnd]

all channels should go to a ground buss, something thick and very conductive that is tied to the channels with thick wires and solid connections.

As was manufactured, my mixer has flat cable, with all busses, and power supply voltage and all those five grounds. And mixer is buzzing a bit no matter those five grounds. (When I got it, ground traces on output PCBs were burnt(melted), so probably there was hi voltage hitting outputs and melting copper on PCBs). Maybe with new power supply it will be quiet, or maybe I also better redo the grounding scheme, while I'm at it.

As I said, I have 5 grounds going through flat cable. Can I connect all 5 grounds together already on each channel board, and then connect that by single wire to single ground bar? But why are now grounds split to five? Do I need to replace that with five thick copper bars, which are then connected only at one end to chasis?

Actually, I really do not get it, why are there five grounds, all labeled differently in schematics. Why are they not connected together already on channel boards, but are instead sent separately through flat cable and then connected together on monitor board? Wouldn't it be the same, if they were connected already on channel boards, and there was just one single ground?

thnx